Hammer mill for stock feed



Jan. 16, 1945. e. D. ARNOLD BAMMERMILL FOR swocx FEED Filed April '7, 1941 iNVENTOR GEQflLO D. yen/0&0

Patented Jan. l6, 1945 v UNITED STATES PATENT OFF-l-CE i This invention relates todmprovements in the a'rtof preserving valuable elements of organic materials, the present-application being a continuation in part of my pending application, same 'title; Serial No. 231,110,

'- Patent No. 2,241,654;

An object of this invention resides in the provision of improved mechanism for comminuting organic material while simultaneously withdrawing heat therefrom preparatory to the'storage thereof. More specifically, it is my object to provide an improved hammermill or grinding mill. wherein herbaceous stock food or other material may illedSeptember 22, 1938, 5

" 1 direct evaporative expansion or with chilhng therefrom preparatory to storage of the material. 2

vA heat extracting device, such as aradiator *1 22, having 'inletand outlet pipes 23 and 24, respectively, may be supplied with refrigerant for brine or other refrigerant, such as cold water, when a supply of such is available. Radiator 22 is placed in a housing in the path of all the air admitted-to hammermill I5 Housing 25 opens into the base '26 of the mill at a point opposite to the junction of pipe 'ili with said base. I

In the apparatus shown in Figure 1, the hammermill IS, with improved cooling means, is coue be comminuted or ground, heat being extracted '15 pl n a Pr d m nner for simultaneous:

from the material both before, during. and after the grinding operation.

Another object of my, invention is to provide w v walled casing 21 widing nofiling jacket 28.

a hammermill with cooling means for extracting grinding and cooling of material such as alfalfa as it passes therethrough. As best shown in Figi ures 2 and 3, the hammermill includeswdoubl heat not only from the outer casing thereof. butszowJaeketriteneles a hammer assemb y 0 rot t also directly from the internal screen or grin d- 1 ing surface.

A further obiectbf the invention is-to generally improve and simplify the construction and operawith'their inner ends" pivotally engaged between successive disks. The'rotor assembly may be cone tion of hammermills for one'or more of the above 25 structed i y Well-known a? purposes, with particular reference to improve-- ments in apparatus wherein herbaceous stock foodis ground and cooled preparatory to thestorage thereof. inthedrawingz Figure 1 ma view in perspective of one formfof i the present invention incor-..

apparatus having porated therein. g l Figure 2 represents in cross seetienanimproved hammermill, such as is shown inFl'gure 1.1

* mg e 3 is a front elevation of'the haniniermill shown imFigure 2; with parts broken away tobest illustrate the construction thereof.

Like-parts are identified by the same reference charactersthroughout the several l Referring to Figure 1, the apparatus includes a feed pipe l0 through which material, such as alfalfa. is delivered into'a, hopper ll, preferably provided with a mechanically driven feeder, such. for example, as a screw conveyor or a rotary valve 12 which admits material along'with; a small amount of air into a, hammermill III In the (embodiment shown, pipe is in sealing relation to hopper l-l, wherebythe only airadmitted into conduit 1 6.

- Incoming material passing through the pipe [0,

' hopper n, metering device-l2, 'and'into casing 21 is ordinarily relatively free from air, especially if the material buildsup-in pipe' l0. An insumcient supply of air-prevents proper distribution of material during the grinding operation. Hence an air-inlet'conduit ,leadiug into the upper portion of casing '21, is'provided to ensure an adequate air supply within the Conduit 4| is connected to housing 25 to draw air-from the interior thereof, after it has been cooled by radiator 22, whereby the cool air entering casing the mill'through'the hopper is the air which is h sh o itl i with. material entrapped in the material being fed. Aftertreatment in the hammermill, as later described, the material .passes out through the discharge pipe .llblower I1, and discharge pipe 18, into a cenbeing fedthrough the metering device [2 to extract heat from the incoming material prior to its being acted upon by the hammer assembly, 30.- A control valve 42 in conduit It provides for selectrifugal separator IS in which the air is separated tive regulation of the amount of air entering the temperatures.

o-L .casing; Likewise, the amount of pro-cooled air, whichis being drawn through trough 38 within base 26 by suction fan I1, is regulated by a valve 43 in the neck of housing 25.

Durin O ration of the device, liquid coolant flows through inlet pipe 24, heat exchanger 22 which may be a radiator or an air washer, and outlet pipe 23, to absorb heat and to be recirculated. Part of the'coolant from inlet pipe 24 flows through (pipe 22 to enter casing jacket 28 of hammermill ii. The coolant circulates throughout the'casing jacket and through conduits 36' which communicate therewith as at 42-42, Figure 3. The coolant leaves jacket 28 at the upper end thereof and flows through conductor 44 to the outlet conduit 23 of radiator 22. Atmospheric air is simultaneously being drawn by fan ll through radiator 22, conduit 25, and in trough 38 to provide a refrigerated air stream flowing through the bottom portion githemill d and in which material passing through screen 35- is entrained, to be removed from the mill and conveyed to separator I!) while further heat is simultaneously extracted therefrom.

Ordinarily a considerable amount of heat is generated within a hammermill during the grinding operation therein. Not only does the triotion caused by grinding substantially raise the temperature of the grinding screen, but a substantial rise in screen temperature raises the temperature of material ground.

In the present device, the coolant flowing ing screen 35 in order to ensure proper action of the mill. If too much air is admitted, grinding is. coarse and uneven, .and if insuihcient air is admittedthe material is thrown about the interior of the casing with little effective grinding action. It is also important to be able tocontrol the amount of air flowing through trough 40, the right amount being determined in accordance with the cooling capacity of radiator 22 as well said casing, means rotatable within said casing tor grinding and forcing material through said screen while simultaneouslyoremovingthe heat therefrom, and means for removing said material while further lowering the. temperature thereof, said means including means for pre-cooling an air stream and propelling said air stream through screen supporting conduits 36 eflectively withdraws the heat generated therein during the grinding operation not only to prevent any undue heating of the screen during grinding, but preferably to keep it at sub-atmospheric Such a cooling operation is ef-. fective in preventing heat transfer from the screen to the material, and referably results in heat extraction from the material during the grinding operation. As previously stated, the

ground material passes through the screen 35, 7 t'o entrained and iurther cooled by the air stream flowing transversely through the bottom of the device along the walls of trough 38.

, During the operation the rotary assembly 30 causes the incoming material to be thrown about considerably within casing 21, durwhich time the material contacting the inner-walls of. jacket 28 is cooled by. conductive heat transfer from the material to the walls, to K be removed bythe coolant flowing through jacket 28. The coolant flowing through jacket 28 substantially lowers the "temperature of the air within the mill, and hence further reduction is obtained in the temperature or the material passingtherethrougln Duringusatherotaryassemblyuactsasa suction Ian to draw pro-cooled air throughconduit 4| into the casing. Itisimportant to admit onl the right amoimt'ofair above the grindtransversely through the lower casing portion in which the material being removed is entrained.

2. Apparatus for grinding and extracting heat from stock feed and the like, including a grinding device comprising a jacketed casing, a feed inlet conduit leading-into an upper portion thereof, means for directing a pro-cooled pneumatic stream transversely of a bottom portion of the casing, a grinding screen intermediate the inlet conduit and said stream directing means, a hammer assembly mounted for rotation adjacent the screen for the grinding'of feed during passage through the device, means for conducting precooled air into the casing intermediate the feed inlet and the grinding screen, conduit means contiguously engaging portions oi'said screen and connected between spaced portions of the jacket, means for circulating a coolant through the casing "jackfand the conduit iorie ex-- traction of heat from material contacting the I inner jacket walls and the screen.

3. Comminuting apparatus comprising a hammermill provided with arhammer assembly in combination with a ioraminous screen and supports for said screen individuallyprovided interiorly with conduits, together with means including connections for passinga refrigerating material. through such conduits, whereby to absorb heat directly from said supports, said screen being in intimate heat conductive relation to said supports, being dependent thereon for support. GERALD D. ARNOLD. 

